High pressure arc discharge lamps are useful in many applications, such as industrial installations, streets, tunnels, underpasses, car parks, courtyards, parks and gardens, buildings, monuments, and bridges, to name a few. Some particularly useful applications for high pressure arc discharge lamps are in areas where it is difficult to replace lamps, due to limited accessibility, such as streets and tunnels. High pressure arc discharge lamps can have a longer life than standard lamps and greater reliability than standard lamps making them the preferred lamp in many such applications.